US 2001/0043059 A1 · Integrated low ripple, high frequency hysteretic controller for DC-DC converters

Abstract

The present invention relates to a hysteretic dc-dc converter circuit comprising a buck converter circuit having an output which forms an output of the converter circuit and a hysteretic comparator circuit having an output coupled to an input of the buck converter circuit and a first input coupled to the output of the converter circuit. The converter circuit also comprises a feedback circuit coupled between the output and a second input of the hysteretic comparator circuit. The feedback circuit generates a feedback ramp signal which is a function of an output of the hysteretic comparator circuit and which is out of phase with respect to the output of the converter circuit. The output feedback coupled with the ramp signal feedback provide for an increased hysteretic comparator trip frequency, thus increasing a natural frequency of the converter circuit without requiring an alteration of the hysteretic window. The present invention also relates to a method of increasing a natural frequency of a hysteretic dc-dc converter circuit. The method comprises initiating operation of a buck converter circuit and feeding back an output signal of the buck converter circuit to a comparator circuit. The method also comprises generating a feedback ramp signal which is out of phase with the output signal, feeding back the generated feedback ramp signal to the comparator circuit, and generating a comparator output signal based on the output signal and the generated feedback ramp signal. Such feedback results in an increase in a trip frequency of the comparator and thus increases a natural frequency of the converter circuit.

Claims20

Dependent claims

A hysteretic dc-dc converter circuit, comprising:

a drive circuit;
an LC filter circuit coupled to the drive circuit, wherein the LC filter has a converter circuit output terminal associated therewith;
a hysteretic comparator circuit having an output coupled to the drive circuit, wherein a first input terminal of the hysteretic comparator circuit is coupled to the output terminal of the converter circuit;
and
a feedback circuit coupled between the output and a second input terminal of the hysteretic comparator circuit,
wherein the converter circuit input is also coupled to the second input terminal of the hysteretic comparator circuit, and wherein the feedback circuit provides a signal that, coupled with an input signal at the converter circuit input, is out of phase with an output signal at the first input terminal, and wherein a comparison of the signals at the first and second input terminals of the hysteretic comparator circuit results in a hysteretic comparator trip frequency which is greater than a trip frequency that would be dictated by a hysteresis window associated with the comparator circuit.

3 more elements

A hysteretic dc-dc converter circuit, comprising:

a buck converter circuit having an output which forms an output of the converter circuit;
a hysteretic comparator circuit having an output coupled to an input of the buck converter circuit and a first input coupled to the output of the converter circuit;
and
a feedback circuit coupled between the output and a second input of the hysteretic comparator circuit,
wherein the feedback circuit generates a feedback ramp signal which is a function of an output of the hysteretic comparator circuit, and wherein the feedback ramp signal is out of phase with respect to the output of the converter circuit.

2 more elements

Dependencies are inferred from the claim text.

Integrated low ripple, high frequency hysteretic controller for DC-DC converters

Life of this patent

Integrated low ripple, high frequency hysteretic controller for DC-DC converters

Life of this patent

Abstract

Claims20